The STEELMAN PRO 96787 100 Lumen Detachable LED Headlamp can produce an impressive amount of light from a single 3 Watt A3 CREE LED bulb. In addition, the light is dimmable to allow for custom illumination perfect for the situation. At full brightness the single CR123 battery can power the light for up to 4-hours to give you plenty of time to get the job done, indoors or outdoors. Constructed of durable black anodized aluminum with sealing O-rings the light is weather-resistant, ideal for outdoor use while camping, even in the rain or snow. The versatile design includes a steel pocket clip, an adjustable/removable headband, and a magnetic base on the light unit for perfect illumination wherever it is needed. This headlamp requires one (1) CR123 Lithium battery which is included for your convenience.